Power over Ethernet (PoE) technology can be used to provide electrical power to multiple electronic devices and/or systems by establishing a PoE power chain. In a typical PoE configuration a Power Sourcing Equipment (PSE) unit is used to source power to a Powered Device (PD) unit. The PSE and the PD units typically reside in separate electronic devices separated by some physical distance and are connected together typically using a RJ-45 type Ethernet cable. The PD provides regulated power to the connected subsystem where the subsystem is located.
The current PoE technology is described in the following patents.
U.S. Pat. No. 9,209,981, entitled: “Power over Ethernet on data pairs and spare pairs” describes a method where a Power over Ethernet Power Sourcing Equipment device is connected to a pair of data wires and a pair of spare wires. When the PSE first powers up if it detects a Powered Device on the data wires it applies power to the data wires via a transistor switch. Next, if it detects a PoE PD device on the spare wires it proceeds to apply PoE power to the spare wires via a second transistor switch. This is a method for a PoE device powering up a PD device directly via a switch. U.S. Pat. No. 9,209,981 is incorporated by reference for all purposes into this specification. In contrast however, one embodiment of the disclosed invention is a method to power a Power Sourcing Equipment device with the output of another Power Sourcing Equipment device.
U.S. Pat. No. 9,203,628, entitled: “Method for apparatus for distributing power over communication cabling”, describes in general about allowing Power Sourcing Equipment devices to power up Powered Device devices “directly” based on the presence of a first or second optional load. This reference does not disclose any PSE devices powering other PSE devices. U.S. Pat. No. 9,203,628 is incorporated by reference for all purposes into this specification. Again, in contrast however, one embodiment of the disclosed invention is a method to power a Power Sourcing Equipment device with the output of another Power Sourcing Equipment device.
U.S. Pat. No. 8,873,370, entitled: “Power over Ethernet management devices and connections between Ethernet devices”, illustrates multiple embodiments that pass or repeat power from one Ethernet port to another. However, in all embodiments either a Power Sourcing Equipment device is powering a Powered Device or in the embodiment where a Powered Device is powering a Power Sourcing Equipment where there is a 48V power conversion. And, in contrast however, one embodiment of the disclosed invention is a method to power a Power Sourcing Equipment device with the output of another Power Sourcing Equipment device. U.S. Pat. No. 8,873,370 is incorporated by reference for all purposes into this specification.
One or more embodiments of the disclosed invention provide a unique and distinct way for applying input power to a PoE Power Sourcing Equipment device in a subsystem to turn on the PSE. One embodiment includes a feature that include local stepped up subsystem voltages, generated by the Powered Device, which are not used to power up the Power over Ethernet PSE. Instead, the input voltage to the subsystem's PD is used and forwarded to the input of the PoE PSE in a protocol timed manner in order not to interfere with PoE power up handshaking. Embodiments of the disclosed invention have numerous advantages over the prior art that include the following features: cost reduction, power heat dissipation reduction, and power efficiency improvement.
In another embodiment of the disclosed invention, a feature is that a PSE Powered Device powering a PD device is used to power a second PSE device. In the PoE protocol, Power Sourcing Equipment devices are intended to only power PD devices in a point to point topology and are not intended to power directly another Power Sourcing Equipment device in a PoE chain.
And in another embodiment of the disclosed invention, a feature is that the Power Sourcing Equipment output voltage of a first PSE is “forwarded” to the input of a second PSE via an intelligent switch that turns on when the first PSE and a PD connected to the first PSE finalize their power up handshake.